SS7 network planning tool

ABSTRACT

Planning alternative SS7 networks is a complex task requiring assistance from an intelligent planning tool. The tool includes at least one planning database containing information on network traffic, component locations, and component connectivity. A load module determines peak load for each STP in the core network. A forecast module determines equipment capacity exhaustion for each STP, network database, and core link during each study period and determines network costs based on peak loads and an alternative network design provided by a user. A graphical user interface guides the user through a sequence of design steps, each step having to be correctly completed before the next step in the sequence is started. The sequence of steps may include permitting changes to the core network, permitting changes to the number of POPs and DBs, rehoming elements left disconnected from STPs, assigning SSPs to POPs, assigning SSPs to DBs, and permitting voluntary rehomes.

TECHNICAL FIELD

[0001] This invention relates to tools for planning Signaling System 7(SS7) communication networks.

BACKGROUND ART

[0002] An SS7 network is a packet data network used for out-of-bandsignaling to perform call set-up and tear-down, to implement AdvancedIntelligent Network (AIN) services, to route traffic to interexchangecarriers (IXCs), and to access database information needed to providecertain services such as 800, LNP, and LIDB. Core components of the SS7network include switches called Signal Transfer Points (STPs). The STPsare interconnected with data links to form a core network.

[0003] Connected to each STP may be several different network elements.Signal Switching Points (SSPs or central offices) route calls.Points-of-Presence (POPs) serve as sources and sinks for networktraffic. POPs provide alternate local carriers and IXCs with access tothe Local Access and Transport Area (LATA) serviced by the STP. Networkdatabases (DBs) support customer services.

[0004] Designing an alternative network includes adding, deleting, andmoving network components, changing component capabilities, adding andmodifying network services, and modifying connectivity betweencomponents. Changes to an existing network can create unintendedsituations. Removing an STP can leave elements disconnected from thenetwork. Removing a database can eliminate a required service. Modifyingconnectivity can create load in excess of capacity on certain links andnetwork components. Designs are further complicated by changing loadsand service requirements over time.

[0005] Traditionally, SS7 network planning has been accomplished throughthe use of spreadsheets. These spreadsheets only model a portion of thenetwork such as, for example, the core network. Another difficulty isthat load information has to be manually entered. Further, graphicaldisplay of the network and the effects of modifying the network arelimited. As network size and complexity increases, the number ofvariables used to model the network is increasing beyond the capacity ofthe spreadsheet. Finally, a user attempting to create an alternativenetwork does not have sufficient guidance and correctness validation.

[0006] What is needed is an SS7 network modeling tool that providesgreater capabilities. The tool should guide a user through thedevelopment of an alternative network design. A graphical user interfaceshould provide the user with an image of the network and allow the userto graphically select network components for modification. The toolshould determine equipment capacity exhaustion due to maximum loadsforecast for each study period and the costs for alternative networks.

SUMMARY OF THE INVENTION

[0007] It is a primary object of the present invention to provide an SS7network modeling tool with greater capabilities than existing tools.

[0008] Another object of the present invention is to guide the userthrough the development of an alternative network design.

[0009] Still another object of the present invention is to provide agraphical user interface showing the user with an image of the networkand allowing the user to graphically select network components formodification.

[0010] A further object of the present invention is to determineequipment capacity exhaustion due to maximum loads forecast for eachstudy period.

[0011] A still further object of the present invention is to determinecosts for alternative networks.

[0012] In carrying out the above objects and other objects and featuresof the present invention, a system is provided for planning a SignalingSystem 7 (SS7) network over a sequence of study periods. The systemincludes at least one planning database containing information onnetwork traffic, network component locations, and network componentconnectivity. A load module determines peak loads for each STP in thecore network based on network traffic, component locations, andcomponent connectivity, and stores the peak loads in the planningdatabase. A forecast module determines equipment capacity exhaustion foreach STP, network DB, and core network link during each study period anddetermines network costs based on peak loads and an alternative networkdesign provided by a user. A graphical user interface guides the userthrough a sequence of designing steps, each step having to be correctlycompleted before the next step in the sequence is started.

[0013] In one embodiment, the sequence of steps through which thegraphical user interface guides the user includes permitting changes tothe core network, permitting changes to the number of POPs and DBs,rehoming elements left unconnected to STPS, assigning SSPs to POPs,assigning SSPs to DBs, and permitting voluntary rehomes.

[0014] In another embodiment, the graphical user interface showsgraphical representations of the network on a display and allows theuser to modify the network by selecting displayed graphicalrepresentations of network components.

[0015] A method is also provided including obtaining network trafficinformation from the network, determining current peak loads for eachSTP based on the network traffic information, and specifying analternative network through a sequence of designing steps, each stephaving to be correctly completed before the next step in the sequencecan be started. For each study period, the method includes forecastingpeak loads for each STP based on the current peak loads for each STP,determining equipment capacity exhaustion for each STP, network DB, andcore network link in the alternative network based on the forecastedpeak loads, and determining costs for the alternative network.

[0016] The above objects and other objects, features, and advantages ofthe present invention are readily apparent from the following detaileddescription of the best modes for carrying out the invention when takenin connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017]FIG. 1 is a block diagram of an SS7 network architecture that maybe planned by the present invention;

[0018]FIG. 2 is a block diagram of an exemplary system according to thepresent invention;

[0019]FIG. 3 is a flow diagram of an embodiment of the present inventiondescribing a method for planning an alternative network;

[0020]FIG. 4 is a flow diagram of steps for creating an alternativenetwork design according to the present invention;

[0021]FIG. 5 is a view of a graphical user interface screen according tothe present invention showing the core network;

[0022]FIG. 6 is a view of a graphical user interface screen according tothe present invention showing a subnet for a specific STP; and

[0023]FIG. 7 is a view of a graphical user interface screen according tothe present invention showing an output graph.

BEST MODES FOR CARRYING OUT THE INVENTION

[0024] Referring now to FIG. 1, an SS7 network architecture is shown. AnSS7 network, shown generally by 20, is comprised of STPs interconnectedby links to form a core network. Several different switch models may beused as STPs. Each model has different capacity and engineeringparameters. Network 20 shown in FIG. 1 has STPs arranged in three tiers,but the present invention applies to any SS7 network configuration.

[0025] Local STP (LSTP) 22 serves a LATA, shown generally by 24. EverySSP 26 in LATA 24 is connected either directly or indirectly to LSTP 22.Connections between SSPs have been omitted for clarity.

[0026] Each LSTP 22 handles inter-LATA traffic to and from the IXCs viaPOPs, one of which is indicated by 28, attached to each LSTP 22. POPs 28provide long distance services to regional Bell operating companies(RBOCs), which would otherwise be prohibited from transporting callsacross the boundaries of LATA 24. POP services include AT&T®, MCI®,Sprint®, and the like. Each SSP is required to have access to each POPservice. Connection between POPs is not shown for clarity.

[0027] Each LSTP may also service one or more network DBs, one of whichis shown as 34. Generally, network DBs are either Service Control Points(SCPs) or Intelligent SCPs (ISCPs). Network DB services include LocalNumber Portability (LNP), Advanced Intelligent Network (AIN), 800 numbertranslation, Custom Local Area Signaling Service (CLASS^(SM)), LineInformation Data Base (LIDB), and the like. Each SSP may be required tohave access to a particular network DB.

[0028] Each LATA 24 belongs to a region, one of which is indicated by30. For the three-tiered network shown in FIG. 1, each LATA 24 withinregion 30 may be connected to one or more territorial STP (TSTP) 32.TSTP 32 may also service SSPs 26 and POPs 28 within a LATA 24. Each TSTP32 in region 36 is connected to regional STP (RSTP) 38. For convenience,any STP will be referenced as 22.

[0029] Referring now to FIG. 2, a block diagram of an exemplarysystem-according to the present invention is shown. An alternative tonetwork 20 is planned to be operated over a sequence of study periods.The configuration and loading of the alternative network is based oncurrent conditions for network 20. Current conditions for network 20 arestored in a planning database, shown generally by 50. In the embodimentshown, planning database 50 is implemented as NETCAM database 52,NetPilot™ database 54, location database 56, and tool database 58. In apreferred embodiment, planning database 50 is implemented using at leastone relational database, such as ORACLE from Oracle Corporation.

[0030] NETCAM database 52 includes traffic numbers, traffic averages,and outages for network 20. This data is collected in near real-timefrom network 20 by NETCAM module 60. NETCAM is a program originallydeveloped by U S West, Inc. and Ericsson, Ltd. NETCAM pull 62 is a setof data describing network 20 over a period, such as a half hour. NETCAMmodule 60 periodically accesses network 20 to obtain NETCAM pull 62 andstores the data in NETCAM database 52. Specific data may include totalmessage signaling units (MSUs) for each STP, global title translation(GTT) counts by translation type of each STP 22, octet loads on corenetwork links, octet loads on SSP A-links, and octet loads on POP links.

[0031] NetPilot™ database 54 includes information on network componentconnectivity. NETPILOT™ from Bell Communication Research is a program tomanage signaling system resources. The data in NetPilot™ database 54describes the core network connectivity between STPs 22 and networkelements connected to each STP 22. The data in NetPilot™ database 54 maybe entered manually without using NETPILOT™.

[0032] Location database 56 includes the location of each component innetwork 20 together with demographic information. In a preferredembodiment, component geographic location is specified using V and Hcoordinates as is well known in the telecommunication art. Informationincludes metropolitan service area (MSA) for each SSP 26, LATA codes foreach SSP 26, North American Numbering Plan (NANP) data, and NXX (localexchange) data.

[0033] Tool database 58 holds data directly accessible by the user asdescribed below. Tool database 58 also holds a location identifier foreach combination of state, city, MSA, and LATA in which a component ofnetwork 20 appears.

[0034] The data in planning database 50 is preprocessed in four modulesindicated as aggregation module 64, configuration module 66, locationmodule 68, and load module 70. Aggregation module 64 reads raw NETCAMdata 72 from NETCAM database 52 collected over a period of time,typically seven days, and condenses the data. This condensed data isstored as aggregated NETCAM data 74 in tool database 58.

[0035] Configuration module 66 accepts raw NETCAM data 72 from NETCAMdatabase 52, raw network element data 76 from NetPilot™ database 54,location data 78 from location database 56, and location identifiers 79from tool database 58. Configuration module 66 can generate a newlocation identifier 79 for a component of network 20 located in acombination of state, city, LATA, and MSA not previously required. Thenew location identifier 79 is stored in tool database 58. Configurationmodule 66 also develops current network configuration data 80 which isstored in tool database 58.

[0036] Location module 68 accepts location data 78 from locationdatabase 56 and organizes location data 78 into a usable form, producingformatted location data 82 which is stored in tool database 58.

[0037] Load module 70 uses aggregated NETCAM data 74 from tool database58 to produce peak hours data 84, which is stored back in tool database58. In order to reduce the complexity of calculations and decreasecalculation time, only peak loads for each STP 22 are used in planningcalculations. These peak loads occur during the busiest one hour over aseven day period.

[0038] Many users may utilize the present invention concurrently.Computer system 86 provides an interface between a user and the presentinvention. As such, computer system 86 includes a display and akeyboard, pointing device, or other data entry and selection tool as isknown in the art. In a preferred embodiment, each user has computersystem 86 running forecast module 88 and graphical user interface (GUI)90. Computer system 86 may be a workstation such as, for example, a SunSPARCSTATION, or a personal computer such as, for example, an AppleMACINTOSH. Alternatively, one or both of forecast module 88 and GUI 90may run on a central computer and computer system 86 may function as aterminal. The precise hardware used to implement computer system 86 isnot critical to the present invention as will be recognized by one ofordinary skill in the art. Descriptions of forecast module 88 and GUI 90are provided with regards to FIGS. 3 through 7 below.

[0039]FIGS. 3 and 4 show flow diagrams illustrating operation ofembodiments of the present invention. As will be appreciated by one ofordinary skill in the art, the operations illustrated in are notnecessarily sequential operations. Similarly, operations may beperformed by software, hardware, or a combination of both. The presentinvention transcends any particular implementation and aspects are shownin sequential flow chart form for ease of illustration.

[0040] Referring now to FIG. 3, a flow diagram of an embodiment of thepresent invention is shown. The flow diagram describes a method forplanning an SS7 network over a sequence of study periods.

[0041] Network traffic information is obtained in block 100. NETCAMmodule 60 automatically obtains NETCAM pull 62 containing informationabout network 20 on a periodic basis. The traffic information isaggregated to show loads for each STP 22 for each hour in a seven dayperiod and is stored in planning database 50.

[0042] Current peak loads for each STP are determined in block 102. Itis possible to perform planning using all of the hourly load informationobtained in block 100. However, this would be computationally expensiveand does not greatly increase the accuracy of planning calculations.Therefore, the hour producing peak loads and the corresponding loadvalues for each STP 22 are extracted and used in planning calculations.

[0043] An alternative network is specified. The goal of planning is todetermine the effects that modifying network 20 may have on current andfuture network performance. The alternative network configuration iscreated by modifying the design of existing network 20. Due to thecomplexity of network 20 and the close interaction of networkcomponents, great care must be taken when modifying the design ofnetwork 20. The present invention guides the user through a sequence ofplanning steps, each step having to be correctly completed before thenext step in the sequence can be started. A preferred sequence ofplanning steps is described with regards to FIG. 4 below.

[0044] To assist in creating the alternative network and in interpretingthe results of planning simulation, GUI 90 displays graphicalrepresentations of the network on a display and allows the user tomodify the network by selecting displayed graphical representations ofnetwork components. Examples of graphical displays are described withregards to FIGS. 5 through 7 below.

[0045] As part of specifying the alternative network, the user may enterthe number of study periods desired. A check is made to see if any studyperiods remain in block 106. If not, simulation is complete.

[0046] Peak loads for STPs are forecast in block 108. For each studyperiod, the peak loads for each STP 22 are determined based on currentSTP loads, network connectivity, changes to services provided, andpredicted demand for services. For each STP 22, loads expressed in callsper second are calculated by peak hour, by service, by study period, andby base year STP pair. Loads for each SSP 26 are found by calculating ascale factor based on the A-link octet traffic from SSP 26 tocorresponding STP 22, then multiplying the base year STP pair load bythe scale factor. Loads are determined for services such as plain oldtelephone service (POTS) local, POTS ATT®, POTS MCI®, POTS Sprint®,CLASS^(SM), 800, LIDB, CND, AIN0.0, AIN0.1, LNP, and the like.

[0047] Equipment capacity exhaustion is determined in block 110. Theability of network components to handle peak loads is found. If loadexceeds capacity for a component, the user is notified. Maximumequipment required for each network component is also determined.

[0048] Cost is determined in block 112. Each component descriptionincludes capital costs such as purchase price and salvage value as wellas expenses such as installation, removal, annual maintenance, yearlylease costs, costs per mile, and the like. The total cost of thealternative network as well as costs by component type and expense typeare determined.

[0049] Peak load forecast, equipment capacity exhaustion, and costdetermination are repeated until every study period has been completed.

[0050] Variations on the above method are possible within the spirit andscope of the present invention as will be recognized by one of ordinaryskill in the art. For example, peak loads may be forecasted for everystudy period prior to determining any equipment capacity exhaustion.

[0051] Referring now to FIG. 4, a flow diagram of steps for creating analternative network design according to the present invention is shown.

[0052] The core network may be changed in block 120. Arbitrary changesto the network of STPs 22 and interconnecting links may be made. In anystudy period, STPs 22 and core links may be installed or retired.

[0053] The core network is checked for validity in block 122. If any STP22 is isolated from the remainder of alternative network 20, alternativenetwork 20 is invalid. If alternative network 20 is invalid, block 120is reentered, allowing the user to modify the alternative core networkdesign.

[0054] POPs and DBs may be added and removed in block 124. POPs 28 andDBs 34 may be installed or retired in any study period. The userspecifies STP 22 to which a modification will be made, the operation tobe performed (add or delete), and the type of element (POP or DB). Inthe case of DB 34 addition, a-name, model, and list of services providedare entered.

[0055] A check is made to determine if all services and traffic issupported in block 126. If the removal of DB 34 leaves network 20without a required service or if the removal of POP 28 leaves network 20without access to a category of IXC traffic, alternative network 20 isinvalid. If alternative network 20 is invalid, block 124 is reentered,allowing the user to install the appropriate DB 34 or POP 28.

[0056] Elements with no STP home are rehomed in block 128. As a resultof removing STP 22, some network elements including SSPs 26, POPs 28,and DBs 34 may be left without a home STP 22. If any disconnectedelements exist, the user is prompted to select a new home STP 22 foreach network element.

[0057] A check is made to determine if all network elements are homed inblock 130. If any network element is not homed to one of STP 22,alternative network 20 is invalid. If alternative network 20 is invalid,block 128 is reentered, allowing the user to rehome network elements.

[0058] SSPs are assigned to POPs in block 132. If POP 28 is retired, SSP26 which was previously assigned to POP 28 no longer has access to theIXC traffic provided by POP 28. Each such SSP 26 must be assigned to POP28 connected to alternative network 20 providing the required IXCaccess.

[0059] A check is made to determine if all SSPs are assigned to POPs inblock 134. If any SSP 26 is not assigned to POP 28 for each IXC accessprovider, alternative network 20 is invalid. If alternative network 20is invalid, block 132 is reentered, allowing the user to reassign SSP 26to an appropriate POP 28.

[0060] SSPs are assigned to DBs in block 136. If DB 34 is retired orsupports a new service, SSP 26 may not have access to the servicesupplied by DB 34. Each such SSP 26 must be assigned to DB 34 connectedto alternative network 20 that provides the required service.

[0061] A check is made to determine if all SSPs are assigned to DBs inblock 138. If any SSP 26 is not assigned to DB 34 for each requiredservice, alternative network 20 is invalid. If alternative network 20 isinvalid, block 136 is reentered, allowing the user to reassign SSP 26 toan appropriate DB 34.

[0062] Voluntary rehomes are performed in block 140.

[0063] At this point, alternative network 20 is valid. However, the usermay desire different STP 22 homes to SSPs 26, POPs 28, and DBs 34, andmay desire different POPs 28 and DBs 34 to service SSP 26. The userselects the affected STP 22 then makes the desired changes.

[0064] A check is made to determine if all rehomes are correct in block142. If any rehome is not correct, alternative network 20 is invalid. Ifalternative network 20 is invalid, block 140 is reentered, allowing theuser to correct voluntary rehomes.

[0065] Referring now to FIGS. 5 through 7, views of displays from agraphical user interface according to an embodiment of the presentinvention are shown. The views are provided as an example of GUI outputand do not represent a complete listing of screens provided.

[0066] Referring now to FIG. 5, a view of a graphical user interfacescreen including the core network is shown. The view appears in awindow, shown generally by 150, on a display that is part of computersystem 86. Subwindow 152 includes a map showing the region of interestand core network components. Menu controls 154 provide access to generalcommands such as load project, store project, begin alternative networkdesign, and the like. Period select control 156 allows a study period tobe specified. The view shown by 150 is of the core network configurationstep, as indicated by display text 158. The user signals completion ofan alternative network design step by selecting next step button 160, atwhich time any user modifications are checked as described with regardsto FIG. 4 above. Pop-up windows, one of which is indicated by 162, allowthe user to specify operations.

[0067] Referring now to FIG. 6, a view of a subnet is shown. For certainoperations, viewing a subnet of network 20 is more convenient. Window170 includes STP listing 172 for selecting STP 22. Once selected, theelements connected to STP 22 are graphically shown in window 174. Inthis view, POPs 28 and DBs 34 are being added and deleted. Pop-up window176 allows data for adding DB 34 to be entered.

[0068] Referring now to FIG. 7, a view of an output graph is shown. Oncesimulation is complete, results may be viewed and printed. Reportsbutton 190 allows the user to obtain various graphs and tables. One suchgraph is shown in pop-up window 192. Maximum and average CPU utilizationis plotted as a function of study period.

[0069] Code for the present invention was written in C, PRO-C by OracleCorporation, and AppBuilder, an graphical development environmentdeveloped at U S West, Inc. As is appreciated by one of ordinary skillin the art, a variety of available software languages could be used toimplement the present invention including VISUAL C++ or VISUAL BASIC,both by Microsoft Corporation.

[0070] While the best modes for carrying out the invention have beendescribed in detail, those familiar with the art to which this inventionrelates will recognize various alternative designs and embodiments forpracticing the invention as defined by the following claims.

What is claimed is:
 1. A system for planning a Signaling System 7 (SS7)network for a sequence of study periods, the SS7 network comprising aplurality of signal transfer points (STPs) interconnected by links toform a core network, each STP having at least one element from a setcomprising signal switching points (SSPs), points-of-presence (POPs),and network databases (DBs), the system comprising: at least oneplanning database comprising information on network traffic, networkcomponent locations, and network component connectivity; a load modulein communication with each of the at least one database, the load moduleoperable to determine peak loads for each STP in the core network basedon network traffic, component locations, and component connectivity andoperative to store the determined peak loads in one of the at least oneplanning database; a forecast module in communication with the at leastone planning database, the forecast module operative to determineequipment capacity exhaustion for each STP, network DB, and core networklink during each study period and to determine network costs based ondetermined peak loads and an alternative network design provided by auser; and a graphical user interface in communication with the forecastmodule and at least one of the at least one planning database, thegraphical user interface operable to guide the user through a sequenceof design steps, each step having to be correctly completed before thenext step in the sequence can be started, thereby producing thealternative network design.
 2. A system for planning an SS7 network asin claim 1 wherein the sequence of steps through which the graphicaluser interface guides the user comprises: permit changes to the corenetwork; permit changes to the number of POPs and DBs; rehome elementsleft unconnected to STPs; assign SSPs to POPs; assign SSPs to DBs; andpermit voluntary rehomes.
 3. A system for planning an SS7 network as inclaim 1 wherein the graphical user interface is further operable to showgraphical representations of the network on a display and to allow theuser to modify the network by selecting displayed graphicalrepresentations of network components.
 4. A method for planning aSignaling System 7 (SS7) network for a sequence of study periods, theSS7 network comprising a plurality of signal transfer points (STPS)interconnected by links to form a core network, each STP having at leastone element from a set comprising signal switching points (SSPs),points-of-presence (POPs), and databases (DBs), the method comprising:obtaining network traffic information from the network; determiningcurrent peak loads for each STP based on the network trafficinformation; specifying an alternative network through a sequence ofdesign steps, each step having to be correctly completed before the nextstep in the sequence can be started; forecasting peak loads for each STPduring each study period based on the current peak loads for each STP;determining equipment capacity exhaustion for each STP, network DB, andcore network link during each study period for the alternative networkbased on the forecasted peak loads; and determining costs for thealternative network for each study period.
 5. A method for planning anSS7 network as in claim 4 wherein specifying an alternative networkcomprises: permitting changes to the core network; permitting changes tothe number of POPs and DBs; rehoming elements left disconnected fromSTPs; assigning SSPs to POPs; assigning SSPs to DBs; and permittingvoluntary rehomes.